JP3075035B2 - Yaw control device - Google Patents

Abstract

PURPOSE:To enable control to stabilize a vehicle regardless of operation of an uncertain driver or a road surface (mu) or the like in vehicle yawing control such as 4WS Of yaw rate F/B control or brake control. CONSTITUTION:A controller 9 sets a target yaw rate according to vehicle speed and a steering angle, and calculates deviation between it and an actual yaw rate (d/dt)phi, and controls yawing of a vehicle, for example, in braking force control according to yaw rate deviation, but also calculates a slip angle according to a signal of a longitudinal/lateral speed sensor 13, and corrects so as to reduce the target yaw rate according to the slip angle when the slip angle is large, and uses the slip angle of the vehicle to detect an unstable condition of the vehicle, and corrects so as to reduce the target yaw rate according to the slip angle when the slip angle is larger than a prescribed value, and controls the yawing of the vehicle, and restricts the slip angle always to a certain range, and stabilizes the vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a yawing control device for controlling yawing of a vehicle.

[0002]

2. Description of the Related Art Conventionally, a device for controlling the yawing of a vehicle includes, for example, a four-wheel steering device controlled by yaw rate feedback (F / B) (Japanese Patent Laid-Open No. 61-1245).
No. 71 publication). Further, a brake control device for yaw rate F / B control is also known (Japanese Utility Model Laid-Open No. 61-196825). In addition, various proposals have been made for a vehicle yawing control device capable of controlling the yawing of the vehicle.

In the yaw rate F / B control, a yaw rate target is set, and the yaw rate of the vehicle can be controlled by driving an actuator of a controlled system so that the actual yaw rate becomes the target yaw rate.

[0004]

The purpose of introducing a control device of this kind is to improve controllability.
In other words, the aim is to improve the maneuverability and stability of the vehicle by controlling the yawing of the vehicle.To determine the yaw rate intended by the driver, the steering input such as the steering angle and the vehicle speed and vehicle characteristic data are used. A target yaw rate is calculated, a control amount for the actuator is determined based on a difference value from a yaw rate actually generated in the vehicle, and the like, and the yawing of the vehicle is controlled so that the actual value follows the yaw rate target value.

[0005] By performing the yawing control of the vehicle based on the target value and the actual value of the yaw rate in this way, the effect of controlling the behavior of the vehicle can be exerted. When considering situations such as
From the viewpoint of emphasizing vehicle stability, the following can be said. For example, when the driver performs wrong steering in a panic state such as obstacle avoidance, or when the driver is an inexperienced driving technique and there is too much turning of the steering wheel or delay in returning, the above-mentioned There is a case where the target yaw rate calculated from the steering angle or the like in the proper vehicle yawing control is not always the best behavior as the vehicle behavior. If the driver turns the steering wheel erroneously in the spin direction during a turn, and as a result, the yaw control device operates yaw control to achieve the set yaw rate target value calculated according to the steering,
It is difficult to re-establish the attitude of the vehicle, and in such a case where the yaw control itself works in an unstable direction of the vehicle due to an uncertain driver's operation, it becomes difficult to secure stability.

Further, for example, the target yaw rate is greatly affected by the road surface μ, and a target on one road surface μ may be inappropriate on another road surface μ, and a correct target suitable for the situation is always set. Sometimes it can be difficult.

The present invention relates to a yawing control for controlling the yawing of a vehicle, which is capable of appropriately controlling the vehicle from a standpoint of stability even in the case of erroneous steering or the like, and capable of controlling the vehicle to be stable. The purpose of the present invention is to provide a control device, which has the following features, and when the slip angle of the vehicle is larger than a predetermined value, interrupts the yawing control according to the yaw rate deviation, The goal is to remove the obstacles to keeping the vehicle stable.

[0008]

According to the present invention, the following yawing control device is provided. That is, target yaw rate setting means for setting a target yaw rate from at least the vehicle speed and the steering angle, yaw rate detecting means for detecting a yaw rate generated in the vehicle, yaw rate deviation calculating means for calculating a deviation between the target yaw rate and the generated yaw rate. Chassis control means for controlling the yawing of the vehicle,
A yaw control device having yaw control means for controlling yaw of the vehicle by the chassis control means in accordance with the yaw rate deviation, wherein a slip angle detection means for measuring or estimating a slip angle of the vehicle; If the value is larger than the yaw rate deviation, the yaw control device (FIG. 2) includes yaw control interruption means for interrupting the yaw control according to the yaw rate deviation.

The yaw control device according to the present invention includes target yaw rate setting means, yaw rate detection means, yaw rate deviation calculating means, chassis control means, and yaw control means, and the target yaw rate setting means includes at least a vehicle speed, a steering angle, and the like. The yaw rate deviation calculating means calculates a deviation between the target yaw rate and the generated yaw rate of the vehicle detected by the yaw rate detecting means, and the yawing control means controls the yawing of the vehicle according to the yaw rate deviation. The yaw of the vehicle is controlled by the chassis control means.
The slip angle detecting means measures or estimates the slip angle of the vehicle, and if the slip angle is larger than a predetermined value, the yawing control suspending means suspends the yawing control according to the yaw rate deviation.

In order to detect an unstable state of the vehicle, the slip angle of the vehicle is used. If the slip angle is larger than a predetermined value, the yaw control according to the yaw rate deviation is interrupted. By stopping the yawing control itself, it is possible to remove the obstacles to maintaining the stability of the vehicle, and in areas where the detected slip angle is large, it can function as a vehicle stabilization device, and uncertain driver operation It is possible to perform control for stabilizing the vehicle irrespective of the road surface μ or the like, and to ensure vehicle stability.

As already mentioned at the beginning of the description, the purpose of introducing such a control device for controlling the yawing of a vehicle is to improve the maneuverability. In other words, the aim is to improve the maneuverability and stability of the vehicle by controlling the yawing of the vehicle.To determine the yaw rate intended by the driver, the steering input such as the steering angle and the vehicle speed and vehicle characteristic data are used. A target yaw rate is calculated, a control amount for the actuator is determined based on a difference value from a yaw rate actually generated in the vehicle, and the like, and the yawing of the vehicle is controlled so that the actual value follows the yaw rate target value. Therefore, by performing the yawing control of the vehicle based on the target value and the actual value of the yaw rate in this way, it is possible to originally exert an effect in controlling the behavior of the vehicle, but this has already been described. As described above, from the viewpoint as follows, that is, from the viewpoint of emphasizing vehicle stability when considering situations such as the following driving and maneuvering scenes, for example, the driver is required to avoid obstacles. If the driver performs wrong steering in a panic state, or if the driver is an inexperienced driving technique and there is too much turning or returning delay of the steering wheel, it is calculated from the steering angle in the vehicle yawing control as described above. The target yaw rate may not always be the best vehicle behavior, and if turning, the driver may incorrectly When the yaw control is performed on the yaw control device side so as to attain the set yaw rate target value calculated and set at least according to the steering (that is, originally for the purpose of improving stability, A target yaw rate in the sense that desired vehicle behavior is realized through the yaw rate F / B control, that is, an attempt is made to follow a target yaw rate determined based on the erroneous steering, instead of a target value appropriate for the control scene. If the control is executed, on the contrary, it becomes difficult to re-orient the vehicle, and if the yaw control itself works in the unstable direction of the vehicle due to the uncertain driver's operation, If it does, it will be difficult to secure stability. Here, as described above, it is useful to stop the yawing control itself according to the yaw rate deviation, and it is possible to remove a factor that hinders the maintenance of such vehicle stability.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. Here, the attached drawings will be briefly described.
FIG. 3 is a system diagram showing one embodiment of the yawing control device of the present invention. FIG. 4 shows a first development example for explaining the yawing control device of the present invention, and is a flowchart showing an example of a control program according to the development example. Note that the first development example was developed by the present inventors simultaneously with the yawing control device of the present invention, and FIG. 1 corresponds to a conceptual diagram of the yawing control device according to the development example. Target yaw rate setting means for setting a target yaw rate from at least the vehicle speed and the steering angle, yaw rate detecting means for detecting a yaw rate generated in the vehicle, a yaw rate deviation calculating means for calculating a deviation between the target yaw rate and the generated yaw rate, and a vehicle. A yaw control device having yaw control means for controlling yaw of the vehicle, and yaw control means for controlling yaw of the vehicle by the chassis control means in accordance with the yaw rate deviation. Angle detecting means, and when the slip angle is larger than a predetermined value, the slip angle It is a conceptual diagram of a yaw control device, characterized in that it comprises a target yaw rate correcting means for correcting to reduce the target yaw rate with respect to increase. FIG. 5 is a diagram showing an example of a characteristic for setting a steady yaw rate applicable to the program of FIG. 4,
FIG. 6 is a diagram showing an example of the characteristic of the target yaw rate correction coefficient, and FIG. 7 is a time chart for explaining an example of the control contents of the program. Here, FIG.
As will be described later, it also shows a target yaw rate setting characteristic that can be applied to the embodiment shown in FIG. FIG. 8 is a flowchart illustrating an example of a control program executed by the controller in the embodiment of the present invention. FIG. 3 is a diagram showing the configuration of an embodiment of the yawing control device of the present invention. This embodiment shows a configuration in which braking force control is used as chassis control for controlling yawing of a vehicle. The vehicle to be applied is capable of independently controlling the left and right braking forces of the front wheels and / or the rear wheels. In the present embodiment, both the front and rear wheels are capable of controlling the left and right braking forces (braking fluid pressure). .

In the figures, 1L and 1R denote left and right front wheels, and 2L and 2R denote left and right rear wheels, respectively. Each wheel is provided with a brake disc 3L, 3R, 4L, 4R and a wheel cylinder (W /
C) 5L, 5R, 6L, 6R, and when the hydraulic pressure from the pressure servo unit (pressure control unit) 7 is supplied to each wheel cylinder of these brake units, each wheel is individually braked.

The pressure servo unit 7 constitutes a braking force control device together with a controller to be described later including the pressure servo unit 7. The pressure servo unit 7 adjusts the oil pressure from the oil pressure generation source 8 according to an input control signal, and controls the wheel cylinders 5L, 5R of each wheel. , 6L, 6R
Control the brake fluid pressure supplied to the Pressure servo unit 7
Is configured to include an actuator for each hydraulic pressure supply system (each channel) on the left and right sides of the front and rear wheels.

As the actuator, for example, an actuator capable of controlling pressure reduction, holding, and pressure increase, which is also used for anti skit control, can be used. In the pressure servo unit 7, an input hydraulic pressure command signal, specifically, a front wheel left hydraulic pressure command value P1 is provided with an actuator for controlling hydraulic pressure of each supply system.
(S), the front wheel right hydraulic pressure command value P2 (S), the rear wheel left hydraulic pressure command value P3 (S), and the rear wheel right hydraulic pressure command value P4 (S). The pressure adjustment of P4 shall be performed.

The above-mentioned signals to the pressure servo unit 7 are supplied from a controller 9 to the controller 9. The controller 9 receives a signal from a treading force sensor 11 for detecting a treading force Fp of a brake petal 10 and a signal acting on the vehicle. A signal from a yaw rate sensor 12 for detecting a yaw rate (d / dt) φ, a signal from an optical speed sensor 13 for detecting the speeds Vx and Vy in the longitudinal and lateral directions of the vehicle, a steering angle of a steering wheel (steering wheel) 14. A signal from the steering angle sensor 15 for detecting δ is input.

The signal from the yaw rate sensor 12 is used as a control parameter in hydraulic pressure control for vehicle behavior control by a yaw rate feedback (F / B) control method.

The controller 9 includes a microcomputer using an input detection circuit, an arithmetic processing circuit, a storage circuit, an output circuit, and the like. When the yaw control of the vehicle is performed by the braking force control, the arithmetic processing circuit will be described later. In accordance with the control program, basically, a target yaw rate is set based on the vehicle speed and the steering angle information, a deviation between the target yaw rate and the actual yaw rate generated in the vehicle is calculated, and the yaw rate of the vehicle is calculated according to the yaw rate deviation. Target wheel cylinder pressure value (command value) as brake force control value to control
And sends a signal corresponding thereto to the pressure servo unit 7. As a result, the pressure servo unit 7 is
The hydraulic pressure from the hydraulic pressure source 8 is adjusted so that the actual wheel cylinder pressure of each wheel matches the target hydraulic pressure, and the hydraulic pressure is supplied to the wheel cylinders 5L, 5R, 6L, and 6R.

In this embodiment, the controller 9 also executes a process of interrupting the yawing control according to the yaw rate deviation under a certain condition. That is, as will be described later (paragraphs 0040 and 0044 to be described later), a target yaw rate is set from at least the vehicle speed and the steering angle, and a deviation between the target yaw rate and the generated yaw rate of the vehicle is calculated. Basically, the target yaw rate is determined while reflecting the driver's intention, and the yaw rate F / B braking force control is performed so that the actual yaw rate becomes the set target yaw rate. However, in such yaw rate F / B braking force control, the slip angle of the vehicle is used to detect the unstable state of the vehicle, and in the unstable state where the slip angle is larger than a predetermined set value, the yaw rate corresponding to the yaw rate deviation A process for controlling to interrupt the control is executed. In this case, the signal from the speed sensor 13 is used to obtain vehicle speed information and is also used as information for measuring the slip angle of the vehicle. It is comprised including a part of.

The present embodiment includes such a control process. Before describing the control of the present embodiment, first, first,
The control according to the development example will be described with reference to FIGS. FIG. 4 is a flowchart illustrating an example of a braking force control program including a target yaw rate correction process according to a slip angle. This processing is performed by a periodic interrupt at a fixed time interval by an operating system (not shown).

First, in step S100, based on the signals from the sensors 11, 12, 13, and 15, the longitudinal speed Vx, the lateral speed Vy, the brake pedal force Fp, the steering angle δ,
The generated yaw rate (d / dt) φ is read.

The following step S101 is a target yaw rate (d / dt) φ ^* setting process. In the first development example, this processing is performed as follows. That is, for example, a steady yaw rate (d / dt) φo is set according to a characteristic diagram of the vehicle as shown in FIG. The figure shows a steady yaw rate (d / dt) φ corresponding to the steering angle δ and according to the vehicle speed.
Here, the relationship of o is shown, and here, the steady yaw rate (d / dt) φo is set from the steering angle δ and the front-rear speed Vx read in accordance with such characteristics. Furthermore, the target yaw rate (d / dt) obtained by adding a delay to the set steady yaw rate (d / dt) φo in accordance with the following equation:
φ ^* .

(D / dt) φ ^* = (d / dt) φo / (1 + τs) 1 where τ is a time constant and s is a Laplace operator.

For setting the target yaw rate,
The present invention is not limited to this example, and may be set based on the vehicle speed and the steering angle, for example, by the following calculation formula.

(D / dt) φ ^* = (δ × Vx) / {A × (1 + K × Vx ² )} ( ² ) where A is a constant determined by the wheelbase and the steering gear ratio of the vehicle. , And K is a constant representing the steering characteristic of the vehicle.

Next, in step S102, a slip angle β of the vehicle is calculated. In the first development example, the following formula is used to calculate the above-described sensor signals, ie, the front-rear speed Vx and the left-right speed Vy.

Β = tan ⁻¹ (Vx / Vy) ≒ Vx / Vy 3

In the first development example, the slip angle β is calculated as described above by detecting the front, rear, left and right speeds by an optical sensor, but other methods are used to obtain the slip angle of the vehicle. May be used. For example, a front-rear and left-right acceleration sensor may be provided to calculate the slip angle β based on the front-rear / left-right acceleration and the yaw rate. Alternatively, the slip angle β may be estimated by having a vehicle model in the controller. Good.

Next, in step S103, the target yaw rate is corrected based on the slip angle β obtained in step S102. In the first development embodiment, for example, using the correction coefficient table shown in FIG. 6, accordingly, the target yaw rate (d / dt) when the calculated slip angle beta value is exceed the set value beta _o phi ^* for correcting the Is determined by the following equation:

## EQU00004 ## The correction is performed in accordance with (d / dt) .phi.h ^* = kh.times ^. (D / dt) .phi. ^* 4.

Here, the value of (d / dt) φh ^{* on the} left side of Equation 4 is obtained by using the correction coefficient kh as a multiplication coefficient in step S10.
6 shows the corrected target yaw rate when applied to the target yaw rate (d / dt) φ ^* value set in FIG.
When the slip angle β is equal to or less than a predetermined value β _o , the correction coefficient kh, which is a multiplication coefficient of the slip angle β, has a value of 1
A is, its properties to take small made from the value 1 as the value beta _o larger than the slip angle beta is increased is set. Accordingly, according to the slip angle β calculated in step S102, if the slip angle β is equal to or smaller than the set value β _o , the process from step S104 onward is performed while the corrected target yaw rate (d / dt) φh ^* remains the target value set in step S102. If the set value is larger than the set value β _o , it is applied to the following processing as a value corresponding to the set target yaw rate corresponding to the correction coefficient kh retrieved from the table based on the slip angle β value. Becomes

The characteristic curve shown in FIG. 6 may be changed according to the vehicle speed. The method of correction is not limited to the method according to the above equation 4, but may be, for example, the set value β of the slip angle.
_The correction amount may be determined according to the deviation between _o and the slip angle β.

After the correction processing in step S103, in subsequent step S104, the corrected target yaw rate (d / dt) φ is set as the yaw rate target value.
Applying the h ^* value, the actual yaw rate (d / dt) φ read in step S100 and the target yaw rate (d / dt)
dt) The deviation Δ (d / dt) φ from φh ^* is calculated according to the following equation.

Δ (d / dt) φ = (d / dt) φh ^* − (d / dt) φ (5)

As described above, the yaw rate deviation Δ (d
/ Dt) Once φ has been calculated, then step S10
5, execute S106. First, in step S105, the target wheel cylinder pressure Pi (i = 1 to 1) for each wheel.
Calculate the reference hydraulic pressure in 4). That is, the brake pedal force Fp
Then, the reference wheel cylinder pressure _Po is calculated. First development
In the example , the reference wheel cylinder pressure _Po is calculated according to the following equation.

[6] Here _{P o = Kt × Fp ··· 6} , Kt is a proportional constant, therefore, the reference wheel cylinder pressure P _o of the reference fluid pressure, the brake pedal pressure Fp
Shall be proportional to

Next, in step S106, in this example,
In order to control the yawing of the vehicle by causing a difference in the braking fluid pressure between the left and right wheels of the vehicle, the yaw rate deviation Δ (d / dt) φ
Target wheel cylinder differential pressure ΔP to be generated on the left and right wheels
Is calculated according to the following equation.

ΔP = k1 × Δ (d / dt) φ 7 Here, the target differential pressure ΔP is such that the yaw rate deviation Δ (d / dt) φ obtained by the above equation 5 is zero. That is, the actual yaw rate (d / dt) φ of the vehicle and the yaw rate target value (d
/ Dt) The target wheel cylinder hydraulic pressure difference for causing the vehicle to generate a yawing torque that eliminates the deviation from φh ^* by the left and right brake hydraulic pressure differences. The proportional constant k1 in Equation 7 is the feedback in the yaw rate feedback control. Gain.

Although only the so-called proportional control is used here, a differential operation or an integral operation may be added. Of course, the feedback control method is not limited to the above-described proportional control method, and may be any one of the differential operation and the integral operation. A control method that takes into account one or both of them is effective in improving the responsiveness and stability of the vehicle with respect to the target yaw rate when improving the operability of the vehicle.

Next, based on the reference wheel cylinder pressure _Po calculated above as a basic value, a target value of the wheel cylinder hydraulic pressure for each wheel is set in order to generate a hydraulic pressure difference required for yawing control on the left and right wheels. I do. That is, in the next step S107, the target wheel cylinder pressure difference [Delta] P, and using the reference wheel cylinder pressure P _o, to calculate a target wheel cylinder pressure Pi of each than these wheels (i = 1~4).

Here, as for the hydraulic pressure difference between the left and right wheels for controlling the vehicle behavior to the target characteristics, for the sake of simplicity, if it is assumed that a pressure difference is generated only on the front wheels, the respective target values Pi Is

[Equation 8] can be set to _{P1 = P o -ΔP ··· 8a P2} = P o + ΔP ··· 8b P3 = P o ··· 8c P4 = P o ··· 8d. Here, the normal front-rear braking force distribution (so-called front-rear distribution by a proportioning valve) is omitted, but may be naturally taken into consideration.

Next, if applicable in steps S108 and S109, processing for setting the Pi value to the value 0 is executed. That is, the calculated target wheel cylinder pressure Pi may be a negative value. In this case, however, the target wheel cylinder pressure Pi is set to 0, and the target wheel cylinder pressure Pi is not reduced to 0 or less. Then, in the next step S110, a brake fluid pressure control process is executed each time this step is executed, and the program is terminated.

The processing content here is a control signal (Pi) corresponding to the hydraulic pressure command value Pi for each wheel determined as described above.
(S)) is individually determined and output to the pressure servo unit 7.
, The actual wheel cylinder fluid pressures P1 to P4 are adjusted according to the above Pi and applied to the wheel cylinders 5L, 5R, 6L, 6R for each wheel.

Thus, according to the above-described control, in the first development example, the stability is improved by the yawing control of the vehicle by the braking force difference control, and the vehicle is always unstable with the slip angle β during the control. If the slip angle β is larger than the set value β _o , it is considered that the vehicle tends to be unstable, and the target yaw rate is corrected in accordance with the slip angle β to reduce the target yaw rate. (Step S103), left and right braking force difference control can be performed (steps S104 to S110). Therefore, even if the vehicle is hit at the time of yaw rate F / B control under such a situation that the driver performs inappropriate steering such that the vehicle becomes unstable as described above, it can be dealt with. Uncertain driver operation and road surface μ
Regardless of the above, control for stabilizing the vehicle is realized whenever applicable.

FIG. 7 shows an example of a situation where the driver further pans in the spin direction in a panic state when the vehicle becomes unstable on a low μ road, for example.
(B) and (c) show the states of the steering angle, the target yaw rate and the actual yaw rate, and the sideslip angle (slip angle β), respectively. Referring to the figure, when the control by the vehicle yawing control device is a control in such a scene, the target yaw rate is determined by the driver using the steering wheel in the comparative example shown by the solid line in FIGS. From the point of time when the angle is increased, the change as shown by the solid line in FIG. (B), the sideslip angle becomes large as shown by the solid line in FIG. (C), and when the spin tendency increases, it is difficult to detect the unstable state of the vehicle. According to this control in which the yaw of the vehicle can be controlled by using the slip angle β and correcting the target yaw rate according to the slip angle β as shown by a dashed line in FIG. In this case, the slip angle β can be kept within a certain range (see the dashed line in FIG. 3C), the spin tendency can be appropriately suppressed, the vehicle can be stabilized, and the stability of the vehicle can be ensured. Is a figure It is.

The case of FIG. 7 is a case where a driver placed under such a situation has erroneously steered in a vehicle unstable direction in view of the result.
As described above, if the device always looks at the slip angle β, if the driver's driving technique is insufficient and the steering wheel is turned too much or there is a delay in returning, if the vehicle becomes unstable due to it To avoid that,
The effect of avoiding the vehicle unstable state and preventing it can be exerted, and the target yaw rate depends on the road surface μ, and the target on one road μ is inappropriate for another road μ. Therefore, simply relying solely on the steering angle and speed cannot always be expected to be a target value suitable for the control scene. It is also a solution to the problem that it is difficult to set a target yaw rate in the sense of realizing through the yaw rate F / B control, that is, a target value appropriate for the control scene. In a region where the slip angle β is large, the vehicle can be made to function as a vehicle stabilizing device that always exerts control in a direction where the slip angle β is within a range that stabilizes the vehicle.

Next, an embodiment of the present invention will be described. This embodiment is a chassis control unit that sets a target yaw rate from at least the vehicle speed and the steering angle, calculates a deviation between the target yaw rate and the generated yaw rate of the vehicle, and controls the yawing of the vehicle according to the yaw rate deviation. The yaw control device for controlling the yaw of the vehicle by the braking force control device and improving the operability of the vehicle is the same as the first development example. Therefore, the system configuration shown in FIG. May be similar. In the first development example, in such a yawing control device, when the slip angle is larger than a certain set value,
Although the target yaw rate is corrected according to the slip angle, in the present embodiment, instead, when the slip angle is larger than a certain set value, the yaw control according to the yaw rate deviation is interrupted. It controls.

FIG. 8 shows the controller 9 in this embodiment.
FIG. 3 is a flowchart showing an example of a control program including a yawing control interruption process executed by (FIG. 3), which is also executed by a periodic interruption at regular intervals.

The processing contents of steps S100, S101, S105 to S110 in FIG. 8 are the same as those in the corresponding steps of the control program in FIG. I do. Also, the yaw rate deviation Δ (d / dt) in FIG.
The φ calculation step S104 is basically the same, but in this example, the target yaw rate (d / dt) φ ^* set in step S101 of FIG. 8 (therefore, the corresponding step of FIG. 4) The target yaw rate (d / dt) φ ^* ) according to the above-described equation 1 or equation 2 described in the description of S101 is directly applied as a target value of the yaw rate in the yaw rate feedback control.

The yaw rate deviation Δ (d / dt) φ is calculated based on Δ (d / dt) φ = (d / dt) φ ^* − (d / dt) φ 9

The main parts will be described below.
After the reading process similar to the case of FIG. 4 in step S100, in the present program example, the following next step S200
Is used to calculate the slip angle β of the vehicle. The processing in this portion may be the same as that described in step S102 in FIG. 4, and may be obtained by estimation.

In the following step S201, step S
The slip angle beta determined in 200 compared with a set value beta _o, if the slip angle beta set value beta _o or less, the target yaw rate (d / dt) of the step S101 phi ^* set below, steps S
The processing up to the brake fluid pressure control at 110 is performed, whereby the yaw rate feedback control is executed. This is the same control content as when the correction coefficient kh has a value of 1 in the first development example. Therefore, similarly, the target yaw rate is determined while reflecting the driver's intention, and the actual yaw rate (d / The yaw rate feedback braking force control can be performed such that dt) φ becomes the set target yaw rate (d / dt) φ ^* .

On the other hand, when β> β _o is satisfied in the comparison in step S201, the yaw rate feedback control is interrupted. That is, when the slip angle beta of the vehicle becomes larger than the set value beta _o from step S201, the processing side of the step S202 to set the target wheel cylinder pressure Pi of each wheel to Pi = P _o is selected, step S202 Is executed through step S110, whereby the wheel cylinder hydraulic pressure (brake pressure) Pi of each wheel is
(I = 1 to 4) is based on the wheel cylinder pressure P _o determined from brake pedal force Fp. At that time, the yaw rate feedback control is stopped. This makes it possible to prevent the vehicle from spinning in the case of a case where the driver makes more cuts in the spin direction as in the case described above, as in the first development example, although the means is different from the first development example. It is possible. As a supplementary note here, as already mentioned at the beginning of the description, the purpose of introducing such a control device for controlling the yawing of a vehicle is to improve the maneuverability. In other words, the aim is to improve the maneuverability and stability of the vehicle by controlling the yawing of the vehicle.To determine the yaw rate intended by the driver, the steering input such as the steering angle and the vehicle speed and vehicle characteristic data are used. A target yaw rate is calculated, a control amount for the actuator is determined based on a difference value from a yaw rate actually generated in the vehicle, and the like, and the yawing of the vehicle is controlled so that the actual value follows the yaw rate target value. Therefore, by performing the yawing control of the vehicle based on the target value and the actual value of the yaw rate in this way, it is possible to originally exert an effect of controlling the behavior of the vehicle (see paragraph 0039 and the like). However, as mentioned above at the beginning of the specification, the following viewpoints are taken into consideration, that is, from the viewpoint of emphasizing vehicle stability when considering the following driving and steering situations. However, the following can be said, for example, when the driver performs wrong steering in a panic state such as obstacle avoidance, or when the driver is an inexperienced driving technique and the steering wheel is overturned or delayed to return. In such a case, the target yaw rate calculated from the steering angle or the like in the vehicle yawing control as described above is not necessarily the best behavior as the vehicle behavior. As in the above case, if the driver turns the steering wheel by mistake in the spin direction when turning, the yaw control device side calculates and sets the target yaw rate according to the steering. When the yaw control is performed as described above (that is, the target yaw rate in the sense that the desired vehicle behavior is originally realized for the purpose of improving the steerability through the yaw rate F / B control), that is, the target value appropriate for the control scene is Instead, if the control is executed to follow the target yaw rate determined based on the erroneous steering, on the contrary, it becomes difficult to re-establish the posture of the vehicle, and uncertain driver operation In such a case where the yaw control itself operates in the unstable direction of the vehicle, it is difficult to secure stability (inversely, on the contrary). Properly made. Here, according to the control of the present embodiment, as described above,
It is useful to stop the yawing control itself according to the yaw rate deviation, and it is possible to remove a factor that hinders the maintenance of such a vehicle.

According to this embodiment as well, control for stabilizing the vehicle can be performed irrespective of uncertain driver operation, road surface μ, etc., and vehicle stability can be ensured in yaw rate F / B control.

Although specific embodiments and modifications have been described above, the present invention is not limited thereto. For example, the chassis control for controlling the yawing of the vehicle is the braking force control based on the system configuration shown in FIG. 3 in the above example, but it is needless to say that the present invention is not limited to this. The chassis control means may be a yaw-controllable left / right or front / rear braking force control device, a front wheel / rear wheel steering control device, a front / rear roll rigidity distribution control device, a total driving force control device, or a driving force distribution control device. One or more control devices may be used, and any other control device can be used as long as it can control the yawing of the vehicle.

Further, even when the braking force control is used, the braking force control device of the embodiment can control the vehicle even when the driver is not braking. However, taking into consideration the uncomfortable feeling due to the braking, only the braking force is controlled. Control may be used. Alternatively, in this case, when braking is not performed, the other chassis control devices mentioned above (for example, distribution control of front wheel side driving force and rear wheel side driving force,
It is also possible to control the distribution of the front wheel roll stiffness and the rear wheel roll stiffness of the suspension, and to control the braking force at the time of braking. You may implement in such a mode of proper use. Further, the chassis control device may be comprehensively controlled according to the magnitude and the change speed of the slip angle. In the embodiment, the anti-skit control is not specifically described. However, there is no problem if the wheel speed of each wheel is detected and the anti-skit control is performed at the same time.
In that case, the braking force control may be yaw control by controlling the slip ratio of each wheel, instead of yaw control by front-rear or left-right differential pressure.

[0049]

According to the present invention, the yaw rate can be controlled by setting a target yaw rate based on at least the vehicle speed and the steering angle and controlling the yaw rate of the vehicle in accordance with a deviation between the target yaw rate and the generated yaw rate of the vehicle. The vehicle slip angle is used to detect a stable state, and when the vehicle slip angle is larger than a predetermined value, the yaw control according to the yaw rate deviation is interrupted. By stopping the vehicle, it is possible to remove the obstacles to maintaining the stability of the vehicle, and in the region where the detected slip angle is large, it can function as a vehicle stabilizing device. Irrespective of the above, control for stabilizing the vehicle can be performed, and vehicle stability can be ensured.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a yaw control device according to a first embodiment of the present invention.
FIG. 4 shows a development example, and is a conceptual diagram of a yawing control device according to the development example.

FIG. 2 is a conceptual diagram of the yawing control device of the present invention.

FIG. 3 is a system diagram showing an embodiment of a yawing control device of the present invention.

FIG. 4 is a flowchart illustrating an example of a control program according to a development example.

FIG. 5 is a diagram showing an example of a characteristic for setting a steady yaw rate applicable to the program.

FIG. 6 is a diagram showing an example of the characteristic of the target yaw rate correction coefficient.

FIG. 7 is a time chart for explaining an example of control contents in the program.

FIG. 8 is a flowchart illustrating an example of a control program executed by a controller according to an embodiment of the present invention.

[Explanation of symbols]

 1L, 1R Left and right front wheels 2L, 2R Left and right rear wheels 3L, 3R, 4L, 4R Brake discs 5L, 5R, 6L, 6R Wheel cylinders 7 Pressure servo unit 8 Hydraulic pressure generator 9 Controller 10 Brake petal 11 Tread force sensor 12 Yaw rate sensor 13 Front and rear / Left and right vehicle speed sensor 14 Steering wheel (steering wheel) 15 Steering angle sensor

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Naoki Maruko 2 Nissan Motor Co., Ltd., 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture (56) References JP-A-5-301574 (JP, A) (58) Survey Field (Int.Cl. ⁷ , DB name) B62D 6/00 B62D 7/14

Claims (1)

(57) [Claims] 1. A target yaw rate setting means for setting a target yaw rate from at least a vehicle speed and a steering angle; a yaw rate detecting means for detecting a yaw rate generated in a vehicle; and a yaw rate deviation for calculating a deviation between the target yaw rate and the generated yaw rate. A yaw control device comprising: a calculating means; a chassis control means for controlling yaw of the vehicle; and a yaw control means for controlling yaw of the vehicle by the chassis control means in accordance with the yaw rate deviation. A yaw control device comprising: a slip angle detecting means for measuring or estimating; and a yawing control suspending means for suspending yaw control according to the yaw rate deviation when the slip angle is larger than a predetermined value.